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Similar brake experience today

Originally Posted by melmiley

I had a very strange experience in my 2006 Prius driving home from work today. I was in stop-n-go traffic, traveling about 5-10 mph, when the cars in front of me slowed to a stop. I stepped on the brake, but I kept rolling. I had to watch myself roll into the car in front of me because absolutely nothing happened when I stepped on the brake. I was not pressing the accelerator. I was definitely pressing the brake.

I'm fortunate I was going very slowly when this happened.

My Prius has 11,000 miles on it. It's up to date on all the services.

Has anyone heard of such a problem with other Priuses? Haven't found anything like this on the internet so far. I'm taking it to the dealership first thing in the morning - would have taken it tonight if they weren't closed..

I was driving along a narrow lane in Gloucestershire/Herefordshire border today and doing less than 20mph - a car appeared going slowly towards me on road only wide enough for 1 car - applied brakes suddenly and just as the incident above the brakes simply didnt work until the last thing and I narrowly missed hitting the car. I would have expected to have stopped easily without concern but my wife, son and I all thought we were not going to stop. I was certain that I hit the brake - not much choice on an automatic as it wasnt the accelerator. The sensation was like riding a bicycle in the wet with old caliper brakes - they just dont grip until the last minute. It was very unnerving and i wonder what it would have been like on a wet road at high speed. The road surface was loose and slightly wet and I suspect this confuded the ABS ir whatever is used to control the braking.

I have also had a brake problem with my 06 Prius, around 15,000 miles. On two occasions the brakes failed to activate for 2 – 3 seconds, then they took effect. On the second occasion I started to swerve to avoid the car in front of me before the brakes took effect. On both occasions I was traveling at slow speeds ( under 30 mph), moving uphill, and braking with the intention of coming to a complete stop. There was no rain, sand or gravel, and the car was not skidding. The anti-skid light went on.

I took the car to the dealership, they could not replicate the problem, they said they could not find anything wrong & were going to return the car to me. I insisted something be done, so they sent a mechanic to observe as I test drove the car. I was not able to get the brakes to fail, but I was able to make the anti-skid light go on when it shouldn’t. The dealership then bled the brakes & returned the car to me.

That same day as I approached a stop light, the car did a strange, very slow anti-lock brake response. The brakes applied, then unapplied with about one to 1 ˝ seconds between each application. On two occasions since then the brakes have not applied for 2 – 3 seconds after I stepped on them. The anti-skid light went on one of those times, the other time I was too busy looking at the road to notice. I was going over a rough road surface, but not a surface on which the car was skidding.

I have noticed the anti-skid light goes on sometimes when the car is not skidding but going over a rough surface.

I really liked the Prius before this happened, but I do not feel it is not a safe car to drive until is resolved.

Like Melmiley, I too had a problen today with the brakes not being there when I needed them. I ended up hitting another car and damaged my 07 Prius.

When I hit the brakes I hit them suddenly and hard, yet I kept on rolling until I hit the other car. They may have slowed me down a little, but not much. Nothing close to the feeling of ABS when it kicks in. I have stopped trucks in a shorter space than I coasted today.

I fully intend to make an issue out of it at the dealership on Monday Morning.

I will keep you posted

By the way, if you have an 07 Prius take it out to an empty parking lot, get it up to speed (20-30MPH) and hit your brakes like your life depended on it. Your life may actualy depend on how it reacts. For me it was pretty scary. I would like to know how other Prius' act in an emergency braking situation.

All things mechanical occasionally have problems. Toyota usually does a great job standing behind their products. The fact they want to know exactly what caused the problem should provide some piece of mind they are working on your behalf. Take a deep breath, all will be OK!

Things happen! It is how they take care of you that counts!

AMEN....Cars are made by assembly lines, which are made by humans, thus none of them are perfect!!!

No loaner car. I had the car towed to the dealership service dept (where I bought the car). The dealership said they couldn't touch the car until a Toyota inspector looks at it. They told me I had to call Toyota "Legal" and report the problem ("product liability claim"). The dealership "quarantined" (their term) the car. The dealership called me a few days later to say the inspector had been there, inspected the car, told the dealership to call me and tell me I can come and pick it up, and the inspector will call me within 30 days. No info from the svc dept about the findings, no way to contact the inspector, no written report. The service dept did tell me that they expect the inspector to tell me that he found no problems, otherwise he would not have told them to release the car to me, but the svc dept wouldn't state that for certain. Basically, the svc dept took a hands off approach and told me the issue is between me and Toyota Headquarters.

Some more detail about the incident:

I had approx 15 feet between me and the car in front of me. The brake did not respond. There is no question in my mind that I applied the brake, not the accelerator. (I checked where my foot was, and I also wasn't accelerating). I had enough time to watch the whole thing unfold. With my foot on the brake, I could not stop my car, and I rolled into the car in front of me. I so surprised and confused by the brake not responding, it didn't occur to me to step on the emerg brake until too late.

There was no damage to either car because I was going very slowly (less than 10mph) and I was well behind the car in front of me.

Bumping into the car in front of me was what stopped me (not my brake). After I was fully stopped, I was able to pull over to the side of the road, and the brakes worked again.

Please don't anyone post back saying what I might have been doing wrong, or how it's impossible for this to happen. It did happen, exactly as I've described. I am posting this only to share information with others so that the body of knowledge about this problem builds. Maybe down the road it will help me or someone else.

I also found a similar experience on priuschat.com from 2006 (post is titled "brake failure 2005 Prius")

These brake problems sound pretty ugly but one of the better gatherings of Prius technologists can be found in "Prius_Technical_Stuff", the YahooGroup. Understand, we're a bit 'anal' about getting into the guts of our Prius so this is not a place to bring advocacy or trivial maintenance questions. But folks in that group are the kind who have and do take Prius apart and figure them out.

Those who have had brake or other unusual, complex Prius problems are welcome to join and post what happened and questions. There are no guarantees but folks in "Prius_Technical_Stuff" are pretty good about offering serious, qualified opinions.

I've had no problems with or reasons to investigate the brake system. Hobbit has done more work and Julian developed a 'regen' hack for an NHW10. We've also had some discussions about the anti-lock features and dealing with marginal traction. So as a suggestion, those who have had these brake problems might want to visit and share the symptoms.

I recently had a problem with the brakes on my 2006 Prius with 20,000 km on it.
I was driving into my garage with my foot on the brake and as I was about to come to a complete stop the car accelerated forward, as if you took your foot off the brake and put it on the accelerator. It hit and destroyed our snowblower which in turn put a hole in the drywall of our garage. I believe it was the snowblower that saved the car from driving right into my house.
Fortunately no one was hurt, my husband was in the passenger seat, with seatselt on and my 6 year old neighbour buckled in her car seat in the back.
I was able to reverse the car a few feet and stop.
I have not driven the car since.
We have an excellent Toyota, dealership, Race Toyota. We called the Sales Manager, who we have bought cars from for over 25 years, on a Saturday evening and he called us back, came over on Sunday morning and drove my husband to the dealership to get a loaner car.
The next morning their service people came and picked up the car along with our snowblower and took it to their dealership.
My husband and I had a very sleepless night as all we could think of was what if it had have been a person we hit rather than our snowblower and wall of our garage. We figure we were really lucky. But we were both unanimous that we did not want to get back behind the wheel of this car.
The sales manager bought out our lease and a few days later we were driving a 2008 Toyota Matrix, which was the car we had driven before leasing the Prius and had always enjoyed driving.
The next day they sent someone over to fix the drywall in our garage and we have been informed our 1 1/2 year old snowblower is not fixable so they will be replacing it for us.
It makes me appreciate having a good Toyota dealership. However, Toyota Canada on the other hand is another story. Our dealership contacted them and because they cannot recreate the problem Toyota Canada will not take any responsibility so our dealership is probably going to be out the money for this mishap.
I have written to Toyota Canada asking them to step up to the plate and take responsibilty for their product. Because if I hear that one of these cars cause injury or death, I will sing like a bird.
These cars are so technological that things are bound to happen, that might not happen to all. I work with computers everyday and am responsible for some troubleshooting. They can do something today and when you call a technician to look the problem it is no longer doing it and they can't fix it unless they can see it happening.
I feel sorry for the people who have had problems and still have to drive these. Saving gas is great and helping the environment is all well and good but at what cost.

Update on my situation, When I took the car to the dealer they found no indication of any problem. No computer codes, we also tested the ABS braking on the back lot and the ABS kicked in as it should. This was nothing like when I had the collision which indicates to me that this is an intermittant problem (the worst kind). I also understand that if they have no indication of the root cause, and all the self diagnostics pass, they wouldn't know where to start with any repairs so nothing was done. I have opened a NHTSA complaint to document the event. I would recommend that any one else who had similar problems do the same.

Update on my situation, When I took the car to the dealer they found no indication of any problem. No computer codes, we also tested the ABS braking on the back lot and the ABS kicked in as it should. This was nothing like when I had the collision which indicates to me that this is an intermittant problem (the worst kind). I also understand that if they have no indication of the root cause, and all the self diagnostics pass, they wouldn't know where to start with any repairs so nothing was done. I have opened a NHTSA complaint to document the event. I would recommend that any one else who had similar problems do the same.

Another update:
I have discovered two things:
First, I can reproduce the issue. It is intermittant, but after several attempts I have found that there is a slight delay between hitting the brakes and any serious reaction of the car, some braking yes, but not full braking.
Second, on my Prius I have noticed that I can always reach the floor with my brake pedal with the hybrid system turned on.
I discussed this with my dealer again, they say that this is normal, that with the Prius the initial braking is in the electric motor so that it can regenerate the batteries, then based on sensors there is an electronically assisted hydraulic braking, and finaly, the ABS system. The dealership told me that the pedal reaching the floor is normal since the system is electronic. My issue is that if the computer doesn't properly interpret the sensors it may not recognize an emergency braking situation right away. If I cannot apply full force to the hydraulic brakes because the pedal is at the end of its range then I will never have 100% unless the computer decides to give me that 100%.

Please give me feedback, does everyone else reach a mechanical stop at the end of their brake pedal range or is this unique to my car? My dealer is telling me that it is designed that way and that a delay in braking is possible as the computer transitions the braking from motor-braking to the electronically assisted hydraulic brake system.